package ua.com.fedorvlasov.lazylist;

import android.R;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.widget.ImageView;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ImageLoader {


    private static final boolean ENABLE_CACHE  = true;

    MemoryCache memoryCache=new MemoryCache();
    FileCache fileCache;
    private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
    ExecutorService executorService;

    public ImageLoader(Context context){
        fileCache=new FileCache(context);
        executorService=Executors.newFixedThreadPool(5);
    }
    
//    final int stub_id= R.drawable.stub;
    public void DisplayImage(String url, ImageView imageView)
    {
        imageViews.put(imageView, url);
        Bitmap bitmap=memoryCache.get(url);
        if(bitmap!=null && ENABLE_CACHE)
            imageView.setImageBitmap(bitmap);
        else
        {
            PhotoToLoad p=new PhotoToLoad(url, imageView);
            executorService.submit(new PhotosLoader(p));
            //imageView.setImageResource(R.drawable.def_icon);
        }
    }

    public void LoadImage(String url, BitmapHandler bitmapHandler) {
        Bitmap bitmap = memoryCache.get(url);
        if (bitmap != null && ENABLE_CACHE) {
            bitmapHandler.setBitmap(bitmap);
            bitmapHandler.run();
        } else {
            PhotoToLoad p = new PhotoToLoad(url, bitmapHandler);
            executorService.submit(new PhotosLoader(p));
        }
    }

    
    private Bitmap getBitmap(String url) 
    {
        File f=fileCache.getFile(url);
        
        //from SD cache
        if (ENABLE_CACHE) {
            Bitmap b = decodeFile(f);
            if(b!=null)
                return b;
        }

        //from web
        try {
            Bitmap bitmap=null;
            URL imageUrl = new URL(url);
            HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();
            conn.setConnectTimeout(30000);
            conn.setReadTimeout(30000);
            conn.setInstanceFollowRedirects(true);
            InputStream is=conn.getInputStream();
            OutputStream os = new FileOutputStream(f);
            Utils.CopyStream(is, os);
            os.close();
            bitmap = decodeFile(f);
            return bitmap;
        } catch (Exception ex){
           ex.printStackTrace();
           return null;
        }
    }

    //decodes image and scales it to reduce memory consumption
    private Bitmap decodeFile(File f){
        try {

            //return BitmapFactory.decodeStream(new FileInputStream(f));
            //decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(new FileInputStream(f), null, o);

            //Find the correct scale value. It should be the power of 2.
            final int REQUIRED_SIZE = 140;
            int width_tmp = o.outWidth, height_tmp = o.outHeight;
            int scale = 1;
            while (true) {
                if (width_tmp / 2 < REQUIRED_SIZE || height_tmp / 2 < REQUIRED_SIZE)
                    break;
                width_tmp /= 2;
                height_tmp /= 2;
                scale *= 2;
            }

            //decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize = scale;
            return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
        } catch (FileNotFoundException e) {}
        return null;
    }
    
    //Task for the queue
    private class PhotoToLoad
    {
        public String url;
        public ImageView imageView;
        public BitmapHandler bitmapHandler;
        public PhotoToLoad(String u, ImageView i){
            url=u; 
            imageView=i;
        }
        public PhotoToLoad(String u, BitmapHandler b){
            url=u;
            bitmapHandler=b;
        }
    }
    
    class PhotosLoader implements Runnable {
        PhotoToLoad photoToLoad;
        PhotosLoader(PhotoToLoad photoToLoad){
            this.photoToLoad=photoToLoad;
        }
        
        public void run() {
            if(imageViewReused(photoToLoad))
                return;
            Bitmap bmp=getBitmap(photoToLoad.url);
            memoryCache.put(photoToLoad.url, bmp);
            if(imageViewReused(photoToLoad))
                return;

            Activity a;
            if (photoToLoad.imageView == null) {
                photoToLoad.bitmapHandler.setBitmap(bmp);
                a = (Activity) photoToLoad.bitmapHandler.context;
                a.runOnUiThread(photoToLoad.bitmapHandler);
            } else {
                BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad);
                a=(Activity)photoToLoad.imageView.getContext();
                a.runOnUiThread(bd);
            }


        }
    }
    
    boolean imageViewReused(PhotoToLoad photoToLoad){
        if(photoToLoad.imageView == null)
            return false;
        String tag=imageViews.get(photoToLoad.imageView);
        if(tag==null || !tag.equals(photoToLoad.url))
            return true;
        return false;
    }
    
    //Used to display bitmap in the UI thread
    class BitmapDisplayer implements Runnable
    {
        Bitmap bitmap;
        PhotoToLoad photoToLoad;
        public BitmapDisplayer(Bitmap b, PhotoToLoad p){bitmap=b;photoToLoad=p;}
        public void run()
        {
            if(imageViewReused(photoToLoad))
                return;
            if(bitmap!=null)
                photoToLoad.imageView.setImageBitmap(bitmap);
            //else
                //photoToLoad.imageView.setImageResource(R.drawable.def_icon);
        }
    }
    
    public static class BitmapHandler implements Runnable{
        private Bitmap bitmap;
        public Context context;
        public BitmapHandler(Context context) {
            this.context = context;
        }
        public void setBitmap(Bitmap b) {
            bitmap = b;
        }
        public Bitmap getBitmap() {
            return bitmap;
        }
        public void run() {

        }
    }

    public void clearCache() {
        memoryCache.clear();
        fileCache.clear();
    }

}
